The objective of this proposal is to gain insight into the central mechanisms underlying the regulation of sympathetic control of brown adipose tissue (BAT). Sympathetic outflow to BAT plays a critical role in thermoregulation and contributes significantly to the regulation of energy expenditure. Impairments or alterations in the regulation of sympathetic output to BAT are associated with potentially life threatening pathological conditions and disease states such as hyperthermia and obesity. The specific aims of this proposal are to determine the specific central nervous system pathways involved in the regulation of sympathetic outflow to BAT during the febrile response. Inhibition of areas implicated in the regulation of sympathetic outflow to BAT will be performed during experimentally induced fever in order to assess their involvement in the febrile response. In addition, the activity of single neurons within areas found to be necessary for the febrile response will be recorded during various physiological and pharmacological manipulations in order to gain a greater understanding of the circuits involved in febrile thermogenesis. Insights gained from these experiments may eventually lead to novel approaches for treating the pathological conditions resulting from disregulation of BAT.